The present invention relates to a holder tray of a compact disc or, more particularly, to a holder tray of a jacket for keeping a compact disc made of a rigid plastic resin which simultaneously satisfies the usually incompatible requirements for the reliableness of holding of a disc thereon and easiness of demounting of the disc therefrom.
A "compact disc" is a recently developed recording medium from which the recorded information can be read out by means of a laser beam. By virtue of the extremely high density and fidelity of the recorded information therein, compact discs are highlighted as a promising recording medium not only as a replacement of traditional phonographic records, mainly, for recording and playing of music but also as a medium for recording of information requisite for controlling and operating various kinds of electronic instruments. Compact disc has a flat disc form having a diameter of, usually, about 120 mm with a center hole of about 15 mm diameter for facilitate exact mounting on a read-out instrument or a compact disc player. When a compact disc is not mounted on a read-out instrument or compact disc player, the compact disc is usually kept in a jacket made of a rigid plastic resin composed of a tray for mounting and holding the disc and a cover put thereon.
The disc tray of a jacket must satisfy several requirements not only in reliableness of holding of the disc during handling and transportation but also in easiness and convenience of mounting of the disc thereon and demounting of the disc therefrom. Since a compact disc is secured on the tray at the center hole by being engaged with the tray, the tray has a structure in the center portion to engage the compact disc thereon. In this regard, various different modifications have been proposed and are practically used for the disc-engagement structure at the center of the tray but none in the prior art is quite satisfactory in respect of the usually incompatible requirements for the reliableness of disc holding and easiness of mounting and demounting of a disc.